PROJECT SUMMARY/ABSTRACT: We propose to hold a two-day conference on June 6 - 7, 2008 at Queen's Landing Inn (Niagara-on-the-Lake, Ontario, Canada). The program will be of interest to pediatric hematologists/oncologists, pediatric nurse practitioners, pediatric psychologists, pediatric oncology social workers, medical oncologists, fellows, residents, interns, clinical research associates and other primary care providers. The topic of fertility and reproduction following treatment of children and adolescents for cancer will be addressed. The goals of the 10th International Conference on Long-Term Complications of Treatment of Children and Adolescents for Cancer will be to: 1) review normal testicular function and spermatogenesis; 2) review experimental male gonadal toxicity; 3) review experimental male germ cell transplantation; 4) review normal ovarian function and assessment of ovarian reserve; 5) review acute and premature ovarian failure; 6) review experimental female fertility preservation; 7) review facilities and techniques for male fertility preservation; 8) review clinical female germ cell transplantation and embryo preservation; 9) review patient attitudes toward male and female fertility preservation; 10) review ethical issues regarding fertility preservation in children and adolescents. The conference will include presentations by nationally and internationally recognized experts in these areas. The conference will facilitate interactions among the investigators of the Childhood Cancer Survivor Study, many of whom attend this conference, and foreign investigators. The conference will facilitate the presentation and discussion of research results, both pertaining to the topic of fertility and reproduction, as well as the broader topic of late effects of treatment of childhood cancer. The attendees at the conference, during informal discussions, will develop hypotheses and preliminary research strategies to be further expanded with their research partners following completion of the conference.